Do you speak ...?

How to ask people whether they speak a particular language, and to say
that you do. This is perhaps the kind of question other people might ask
you, and it's useful to be able to understand it and to have an answer
prepared.

Key to abbreviations: inf = informal, frm = formal, m = said by men,
f = said by women, >m = said to men, >f = said to women, sg = said to
one person, pl = said to more than one person.